1. FIELD OF THE INVENTION
The present invention relates generally to an internal combustion engine operable with a mixture of air and a fuel such as hydrocarbon fuel (for example, gasoline) or alcohols (for example, methyl alcohol) and, more particularly, to a fuel reforming system for converting a rich mixture of air and the fuel into an easily combustible reformed gaseous mixture containing hydrogen and for feeding the reformed gaseous mixture into a combustion chamber or chambers of the engine for the improved combustion therein to thereby reduce the emission of the harmful components of the engine exhaust gases.
2. Description of the Prior Art
In order to reduce the harmful components of engine exhaust gases, there has been proposed an intake system for an internal combustion engine. The proposed intake system was provided with a fuel reforming system in which a hydrocarbon fuel such as gasoline was merely added with water, air and the engine exhaust gas to form a mixture which was then introduced into a reactor provided with a catalyst for the catalytic reaction between the components of the mixture at a temperature of from about 250 to about 1,000.degree. C. so that a part of the fuel was reformed into hydrogen, carbon monoxide and/or methane to be fed into the engine. There has also been proposed another type of intake system designed to supply an associated engine with a mixture of hydrogen gas from a hydrogen container and a hydrocarbon fuel from a fuel tank.
The proposed fuel reforming system of the first-mentioned type of intake system required a water container, which caused a problem that the water in the container was frozen with a burst of the container in winter season or a cold district. In the case where the fuel used contained a compound of lead, the engine exhaust gas recirculated into the reactor contained the lead compound by which the catalyst was damaged. Even in the case where the fuel did not contain the lead compound, soot and/or tar was included in the engine exhaust gas and deposited on the surface of the catalyst carrier to reduce the efficiency of the catalyst. The reformed gaseous mixture, moreover, included gaseous components which were unnecessary for the engine operation and which reduced the efficiency of charge of the reformed gaseous mixture into the combustion chambers of the engine and adversely affected the engine performance.
The second-mentioned type of intake system required a hydrogen container which was accompanied by a danger of explosion, inevitably bulky in size and heavy. Thus, this type of intake system was not suitable for an internal combustion engine for an automobile.